The present invention relates to an electric toothbrush.
In general, the electric toothbrush comprises a case body which is divided into a front portion mounting a vibrating device therein and a rear portion as a handle, and a brush portion attached to a front end of the front portion by a connecting shaft projecting from the front end. The front portion is vibrated by the vibrating device, and the vibration is transmitted to the brush portion through the connecting shaft.
The vibration of the front portion is also transmitted to the rear portion as a handle. As a result, the vibration is not effectively transmitted to the brush portion, which means a reduction of vibration efficiency. In addition, the vibration is further transmitted to a hand of a user, thereby giving an unpleasant feeling to the user.
The conventional electric toothbrush has another disadvantage as described below.
the case body is made of plastic and the connecting shaft for attaching the brush portion is integrally formed on the front end of the front portion. When brushing teeth with the electric brush, the brush portion is pressed against teeth and/or gums. Therefore, a lateral force is applied to the connecting shaft through the brush portion. Since the connecting shaft is made of plastic and has a comparatively small diameter, the connecting shaft is liable to be elastically bent to form a gap between the brush portion and the case body. Therefore, the vibration transmitting effect reduces. Furthermore, it happens that the brush portion falls from the case body in an extreme case.